Diaphragm for radio loud speakers



Feb. 16, 1932. c DUFFY I 1,845,584

DIAPHRAGM FOR RADIO LOUD SPEAKERS Filed March 51, 1931- //1 ran/0P,

Patented Feb. 16, 1954 PATENT OFFICE CHARLES HUGH DUFIiY, OI MIAMI, FLORIDA DIAPHRAGM FOR RADIO LOUD SPEAKERS Application fled March :1, 1931 Serial No. 528,863.

(GRANTED UNDER THE A010! men 8, 1888, AS AMENDED AIPBIL 30, 1928; 370 O. G. 757) The invention described herein mayfie manufactured and used by or for the Govern- 7 and preferably into two substantially quarter-circle formations, I have found that when the diaphragm is pulsated by a drive unit or units appliedv to the central meeting-edgeportions of the flexed diaphragm, there exists a tendency for the diaphragm to whip along the central meeting-edge-portions, so that the end portions of the diaphragm do not pulsate uniformly with the intermedlate portions thereof, but under the influence of imparted pulsations of large amplitude, the said end portions pulsate out of step with the central portion of the diaphragm.

For the highest efliciency, it is desirable that the entire central meetin g edge portions of the diaphragm move bodily and uniformly in response to the pulsations impressed upon it. If there be any whipping of the end portions out of step with the central ortion of the diaphragm, such whipping is taken up by the entire diaphragm and it is set in a state of false vibration or chattering,

T which is highly detrimental to the purity and fidelity of the reproduced sound.

This present invention seeks to correct this tendency in .diaphragms ofthis class, and thereby enhance their efliciency.

Referring to the accompanying draw- 1ngs.

Fig. 1 is a diagrammatic side elevation of a diaphragm constructed in accordance with this invention.

Fig. 2 is a top plan view of the same.

Fig. 3 is a horizontal sectional view of such a diaphragm made of celluloid or material of l1ke characteristics.

Fig. 4 is a similar view of a modification of a diaphragm of such material, and

Fig. 5 is a similar view of a further modification.

Like numerals of reference indicate the same parts throughout the several figures, in which 1 indicates the diaphragm, which when constructed as shown in Figs. 1 and 2 may be of any suitable diaphragm material. The diaphragm 1 when so constructed may be made of two sheets of material 2, joined together at 3. It will be seen that I prefer to have the line of juncture 3 of the sheets curved rearwardly from the ends to the center so that the two ends 4 of the diaphragm are reduced in area to less than the area of the intermediate portion. When the diaphra m is flexed the transverse curvature of the exed sheets progressively change from the center of the diaphragm toward both ends thereof as indicated in Fig. 2. The effect of this is that when the side edge portions 5 are clamped to hold the diaphragm in operative flexed position, the end portions are slightly stiffened, and of course, the diaphragm is gradually reduced in area and mass toward the end portions.

Referring to Fig. 1, it 'will be seen that the material forming the diaphragm extends materially in rear of the line of juncture 3 of the flexed sheets to form a positive stiffening area 6, and as shown in Fig. 2, a layer of sound damping material 7 may be interposed between the sheets of diaphragm material throughout the whole of this stiffening area, or this'layer 7 may be of suitable 85 stiff material different from that of the diaphragm material as proposed for Fig. 5. Throughout this stiffening area 6, the diaphragm material is preferably flat and without transverse curvature, so as to present an 90 area of material lying edgewise in the direction of the plane of the impressed pulsations, the extent of which stiffening area is sufli cient to prevent the end-portions 4 of the diaphragm from whipping out of step with the intermediate portion of the dlaphragm upon which the pulsations are impressed and to insure that the entire central meeting edgeportion 8 of the diaphragm moves bodily in response to the pulsations impressed upon the stiffening area/6 by the actuating unit or .two flexed diaphragm portions 2 and leave unsplit the stiffening area 6. In such construction the diaphragm portions 2 are integral and there' is no need for the sound damping material at the stiffening area, because the flexed portions 2 of the diaphragm will be sufficiently and effectually spaced apart by the unsplit stiffening area 6 so that these flexed portions 2 will not strike against each other when ina state of vibration.

Referring to Fig. 4, it will be seen that such a diaphragm of celluloid or of material of like characteristics may be made to form an integral structure by inserting a piece 6 of the same material as that of the diaphragm proper between the lapping surfaces which form the stiffening area 6. A material such as celluloid may, by the application of a suitable solvent to the surface thereof, be caused to unite with the surface of a piece of like material to form an integral or uni,- tary structure. When, therefore, the surfaces of the spacing piece 6 and those of the immediately adjacent diaphragm portions 2 are treated by a suitable solvent or otherwise made plastic by any known manner, and such surfaces united by pressure, a unitary structure will be the result, which will be substantially the same as when the diaphragm is split from a single thick sheet of material as illustrated in Fig. 3.

Referring to Fig. 5, it will be seen that the stiffening area 6 may be made of apiece 7 of suitable stiff material which spaces the diaphragm formations apart and which may or may not be of the same material as that of the diaphragm portions 2. With such construction, I may interpose a thin layer 8 of sound damping material such as felt between the contiguous surfaces of the piece 7 and of the diaphragm portions 2, so that concurrent vibration of the contiguous surfaces will not result in the surfaces striking each other when in a state of vibration.

The invention is susceptible of further modifications, those herein described being by way of example. In each instance, however, it is preferable to construct the diaphragm with a stiffening area of sufficient capacity to insure against whipping of the ends of the diaphragm so that it cannot pulsate out of step with the intermediate portion, and so that it will insure the whole central meeting edge portion of the diaphragm moving bodily in response to the pulsations impressed upon the stiffening area 6 by the actuating unit or units.

While the word celluloid is recited in several of the claims, it is intended that such word define also such materials as may have characteristics like the well known characteristics of celluloid, but which may be known under or designated by other trade-names.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A diaphragm for radio loud speakers or the like of substantially partially circular .formations having a central meeting portion,

edge portions and end portions, the line of juncture at the central meeting portion being curved rearwardly from the ends to the center, and a positive stiffening area in rear of the line of juncture of the flexed portions, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed portions of the diaphragm.

2. A diaphragm for radio loud speakers or the like of suitable material flexed into substantially quarter-circle formations, having a central meeting portion, edge portions and end portions, the line of juncture at the central meeting portion being curved rearwardly from the ends to the center, and a positive stiffening area in rear of the line of juncture of the flexed portions, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of. the two flexed portions of the diaphragm. I

3. A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially partially circular formations having a central meeting portion, edge portions and end portions, a positive stiffening area in rear of the line of juncture of the flexed portions, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed portions of the diaphragm.

4. A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, a positive stiffening area in rear of the line of juncture of-the flexed portions, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed portions of the diaphragm.

5. A diaphragm for radio loud speakers or the like of celluloid flexed into two substantially partially circular formations having a central meeting portion, edge portions and end portions, the line of juncture at the central meeting portion being curvedrearwardly from the ends to the center, and a positive stiffening area in rear of the line of juncture of the flexed portions, said stiffening area being of a. capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed portions of the diaphragm.

6. A diaphragm for radio'loud speakers or the like of celluloid flexed into two sub- .stantially quarter-circle formations having a central meeting portion, edge portions and end portions, the line of juncture of the central meeting portion being curved rearward-- ly from the ends to the center, and a positive stiffening area in rear of the line of juncture of the flexed portions, said stiffening area being of a capacity sufficient-to prevent whip ping of the end portionsf'and insure bodily movement of the entire central meeting por tion of the two flexed portions of the diaphragm.

7 A diaphragm for radio loud speakers or the like of celluloid flexed into two sub stantially partially circular formations having a central meeting portion, edge portions and end portions, a positive stiffening area in rear of the line of juncture at the central meeting portion of the flexed portions, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement 01 the entire cen- Ll'ill meeting portion of the two flexed portions of the diaphragm.

8. A diaphragm for radio loud speakers or the like of celluloid flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, a positive stiffening area in rear of the line of juncture at the central meeting portion of the flexed portions, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed portions of the diaphragm.

9. A diaphragm for radio loud speakers or the like of celluloid flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, the line of juncture at the central meeting portion being curved rearwardly from the ends to the cent-er to gradually reduce the mass and inertia toward the end a, portions.

10. A diaphragm for radio loud speakers or the like of celluloid flexed into two sub stantially partially circular formations having a central meeting portion, edge portions, ard end portions, the line of juncture at the central meeting portion being curved rearwardly from the ends to the center to gradually reduce the mass and inertia toward the end portions.

11. A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, the line of juncture at the central meeting portion being curved rearwardly from the ends to the center to gradually reduce the mass and inertia toward the end portions.

12. A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially partially circular formations having a central meeting portion, edge portions and end portions, the line of juncture at the central meeting portion being curved rearwardly from the ends to the cen- "ter to gradually reduce the mass and inertia toward the end portions.

13.' A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, the line of juncture at the central meeting port-ion progressing rearwardly from the ends to the center-of the diaphragm to gradually reduce the mass and inertia toward the end portions.

14. A diaphragm for radio loud speakers or-the like of celluloid flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, the line of juncture at the cen tral meeting portion progressing rearwardly from the ends to the center of the diaphragm to gradually reduce the mass and inertia toward the end portions.

15. A diaphragm for radio loud speakers or the like formed of a sheet of celluloid partially split to provide two diaphragm portions adapted to be flexed into substantially partially circular formations, the unsplit portion of the sheet lying in rear of the two diaphragm portions to form a stiffening area.

16. A diaphragm for radio loud speakers or the like formed of a sheet of suitable material partially split to provide two diaphram portions adapted to be flexed into substantially partially circular formations, the unsplit portion of the sheet lying in rear of the two diaphragm portions to form a stiffening area.

17. A diaphragm for radio loud speakers or the like formed of a sheet of suitable material partially split to form two diaphragm portions, the unsplit portion of the sheet forming a central meeting portion for the two diaphragm portions.

18. A diaphragm for radio loud speakers or the like formed of a sheet of celluloid partially split to form two diaphragm portions, the unsplit portion of the sheet formlng a central meeting portion for the two diaphragm portions.

19. A diaphragm for radio loud speakers or the like including two diaphragm portions of celluloid, a strip of celluloid disposed between the two diaphragm portions to space them apart, the surfaces of the said strip and the surfaces of the two diaphragm portions in contact therewith being united to form a unitary structure.

20. A diaphragm for radio loud speakers or the like includlng two diaphragm portions flexed into two substantially partially circular formations, a strip of stiff material interposed between the two diaphragm portions at the central meeting portions thereof to space the same apart, said strip of stiff material extending in rear of and beyond the line of juncture of two diaphragm portions to form a positive stiffening area for the diaphragm.

21. A diaphragm for radio loud speakers or the like, of suitable material flexed into two substantially partially circular formations having a central meeting portion, edge portions and end portions, the substantially partially circular formations being spaced apart at the line of their juncture, a positive stiffening area in rear of the line of juncture of the flexed formations, said stiffening area being of a capacity suflicient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed formations of the diaphragm.

22. A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, the substantially quartercircle formations being spaced apart at the line of their juncture, a positive stiffening area in rear of the line of juncture of the flexed formations, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed formations of the diaphragm.

23. A diaphragm for radio loud speakers or the like of celluloid flexed into two substantially partially circular formations having a central meeting portion, edge portions and end portions, the substantially partially circular formations being spaced apart at the line of their juncture, a positive stiffening area in rear of the line of juncture at the central meeting portion of the flexed formations, said stiffening area being of a capacity sufiicient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the two flexed formations of the dlaphragm.

24. A diaphragm for radio loud speakers or the like of celluloid flexed into two substantially quarter-circle formations having a central meetingportion, edge portions and end portions, the substantially quarter-circle formations being spaced apart at the line of their juncture, a positive stiffening area in rear of the line of juncture at the central meeting portion of the flexed formations, said stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the diaphragm.

25. A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially partially circular formations having a central meeting portion, edge portions and endportions, a layer of stiff material interposed between the substantially partially circular formations to space the same apart at their line of juncture, the diaphragm material and the interposed stiffening layer extending in rear of the line of juncture of the flexed formations to form a positive stiffening area of suflicient capacity to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the flexed formations of the diaphragm.

26. A diaphragm for radio loud speakers or the like of suitable material flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, a layer of stifl material interposed between the flexed formations to space the same apart at their line of juncture, the diaphragm material and the interposed stifl'ening material extending in rear of the line of uncture of the flexed formations to form a positive stiffening area of suflicient capacity to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the flexed formations of the diaphragm.

27. A diaphragm for radio loud speakers or the like of celluloid flexed into two substantially partially circular formations having a central meeting portion, edge portions and end portions, a positive stiffening area including continuations of the diaphragm and a piece of stiff material interposed between the diaphragm continuations and spacing the flexed formations apart, at their line of juncture. the stiffening area being of a capacity sufficient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the diaphragm.

28. A diaphragm for radio loud speakers and the like of celluloid flexed into two substantially quarter-circle formations having a central meeting portion, edge portions and end portions, a positive stiffening area in rear of the line of juncture of the flexed formations, the stiffening area including a piece of still? material interposed between continuations of the diaphragm material and spacing the flexed formations apart at their line of juncture, the stifiening area being of a capacity sufiioient to prevent whipping of the end portions and insure bodily movement of the entire central meeting portion of the diaphragm.

In testimony whereof I aflix my signature.

CHARLES HUGH DUFFY. 

